Set Default Monitor #730

dasaintgray · 2023-06-21T03:10:15Z

dasaintgray
Jun 21, 2023

Possible to control or set the default display or make the Main display using the package. Thanks

Jun 22, 2023

Here is an example that enumerates all displays and prints their information. Additionally, you can set a specific display as the primary display by calling its setAsPrimary() method or change the resolution of a display by using its resolution setter.

Hope this helps!

// ignore_for_file: camel_case_types, constant_identifier_names

import 'dart:ffi';

import 'package:ffi/ffi.dart';
import 'package:win32/win32.dart';

void main() {
  // Enumerate all displays and print their information
  for (final display in Display.findAll()) {
    print('Display name: ${display.name}');
    print('Is connected: ${display.isConnected}');
    print('Is primary: ${display.isPrimary}');

    if (display.i…

View full answer

halildurmus · 2023-06-21T16:31:24Z

halildurmus
Jun 21, 2023
Maintainer

Based on my findings, there are no available WinRT APIs that offer control or the ability to set the default display. However, it's possible to utilize Win32 APIs for such purposes. I'm transferring this discussion to the dart-windows/win32.

I plan to create an example for this tomorrow.

1 reply

dasaintgray Jun 22, 2023
Author

Thanks Sir @halildurmus

halildurmus · 2023-06-22T09:25:41Z

halildurmus
Jun 22, 2023
Maintainer

Here is an example that enumerates all displays and prints their information. Additionally, you can set a specific display as the primary display by calling its setAsPrimary() method or change the resolution of a display by using its resolution setter.

Hope this helps!

// ignore_for_file: camel_case_types, constant_identifier_names

import 'dart:ffi';

import 'package:ffi/ffi.dart';
import 'package:win32/win32.dart';

void main() {
  // Enumerate all displays and print their information
  for (final display in Display.findAll()) {
    print('Display name: ${display.name}');
    print('Is connected: ${display.isConnected}');
    print('Is primary: ${display.isPrimary}');

    if (display.isConnected) {
      print('Display resolution: ${display.resolution.prettify()}');
      print('Supported resolutions:');
      for (final resolution in display.supportedResolutions) {
        print(' - ${resolution.prettify()}');
      }
    }

    print('');
  }

  // You can use Display.findByName method to find the display you want to set
  // it as the primary display:
  // final display = Display.findByName('DISPLAY2');
  // if (display != null && display.isConnected) {
  //   display.setAsPrimary();
  // }
}

/// A display monitor.
class Display {
  final String name;
  final String rawName;
  final int _deviceIndex;
  final int _stateFlags;

  Display._(this.rawName, this._deviceIndex, this._stateFlags)
      : name = rawName.replaceAll(RegExp(r'[^a-zA-Z\d]'), '');

  /// Returns the primary [Display].
  static Display get primary =>
      findAll().firstWhere((display) => display.isPrimary);

  /// Finds a [Display] by its [name] (e.g. `DISPLAY2`).
  static Display? findByName(String name) =>
      findAll().where((display) => display.name == name).firstOrNull;

  /// Returns all [Display]s on the system.
  static Iterable<Display> findAll() sync* {
    final pDevice = calloc<DISPLAY_DEVICE>();
    final device = pDevice.ref..cb = sizeOf<DISPLAY_DEVICE>();

    var deviceIndex = 0;

    while (EnumDisplayDevices(nullptr, deviceIndex, pDevice, 0) != FALSE) {
      yield Display._(device.DeviceName, deviceIndex, device.StateFlags);
      deviceIndex++;
    }

    free(pDevice);
  }

  /// Returns `true` if the [Display] is connected.
  bool get isConnected =>
      (_stateFlags & DISPLAY_DEVICE_ACTIVE) == DISPLAY_DEVICE_ACTIVE;

  /// Returns `true` if the [Display] is the primary display.
  bool get isPrimary =>
      (_stateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE) ==
      DISPLAY_DEVICE_PRIMARY_DEVICE;

  /// Sets the [Display] as the primary display.
  void setAsPrimary() {
    assert(isConnected);

    if (isPrimary) {
      print('This display is already set as the primary display.');
      return;
    }

    using((arena) {
      final pDevice = arena<DISPLAY_DEVICE>();
      final device = pDevice.ref..cb = sizeOf<DISPLAY_DEVICE>();

      var result = EnumDisplayDevices(nullptr, _deviceIndex, pDevice, 0);
      if (result == FALSE) {
        print('Failed to get display devices.');
        return;
      }

      final pDeviceName = device.DeviceName.toNativeUtf16(allocator: arena);
      final pMode = arena<DEVMODE>();
      final mode = pMode.ref;

      result = EnumDisplaySettings(pDeviceName, ENUM_CURRENT_SETTINGS, pMode);
      if (result == FALSE) {
        print('Failed to get current display settings.');
        return;
      }

      final offsetX = mode.dmPosition.x;
      final offsetY = mode.dmPosition.y;
      mode.dmPosition.x = 0;
      mode.dmPosition.y = 0;

      result = ChangeDisplaySettingsEx(pDeviceName, pMode, 0,
          CDS_SET_PRIMARY | CDS_UPDATEREGISTRY | CDS_NORESET, nullptr);
      if (result != DISP_CHANGE_SUCCESSFUL) {
        print('Failed to change display settings.');
        return;
      }

      var deviceIndex = 0;

      // Update remaining displays
      while (EnumDisplayDevices(nullptr, deviceIndex, pDevice, 0) != FALSE) {
        final device = pDevice.ref;

        if (_isAttachedToDesktop(device.StateFlags) &&
            deviceIndex != _deviceIndex) {
          final pDeviceName = device.DeviceName.toNativeUtf16(allocator: arena);
          final pMode = arena<DEVMODE>();
          final mode = pMode.ref;

          result =
              EnumDisplaySettings(pDeviceName, ENUM_CURRENT_SETTINGS, pMode);
          if (result == FALSE) {
            print('Failed to get current display settings.');
            return;
          }

          mode.dmPosition.x -= offsetX;
          mode.dmPosition.y -= offsetY;

          result = ChangeDisplaySettingsEx(
              pDeviceName, pMode, 0, CDS_UPDATEREGISTRY | CDS_NORESET, nullptr);
          if (result != DISP_CHANGE_SUCCESSFUL) {
            print('Failed to change display settings.');
            return;
          }
        }

        deviceIndex++;
      }

      // Apply settings
      result = ChangeDisplaySettingsEx(nullptr, nullptr, 0, 0, nullptr);
      if (result != DISP_CHANGE_SUCCESSFUL) {
        print('Failed to change display settings.');
        return;
      }
    });
  }

  bool _isAttachedToDesktop(int stateFlags) =>
      (stateFlags & DisplayDeviceStateFlags_AttachedToDesktop) ==
      DisplayDeviceStateFlags_AttachedToDesktop;

  /// Returns `true` if the [Display] supports the given [resolution].
  bool supportsResolution(Resolution resolution) {
    assert(isConnected);
    return supportedResolutions.contains(resolution);
  }

  /// Gets the [Display]'s current resolution.
  Resolution get resolution {
    assert(isConnected);

    final pDisplayName = rawName.toNativeUtf16();
    final pMode = calloc<DEVMODE>();
    final mode = pMode.ref..dmSize = sizeOf<DEVMODE>();

    try {
      final result =
          EnumDisplaySettings(pDisplayName, ENUM_CURRENT_SETTINGS, pMode);
      if (result == FALSE) {
        throw Exception('Failed to get current display settings.');
      }

      return (width: mode.dmPelsWidth, height: mode.dmPelsHeight);
    } finally {
      free(pMode);
      free(pDisplayName);
    }
  }

  /// Sets the [Display]'s resolution to the given [resolution].
  set resolution(Resolution resolution) {
    assert(isConnected);

    if (!supportsResolution(resolution)) {
      print('Display does not support resolution ${resolution.prettify}.');
      return;
    }

    final (:width, :height) = resolution;

    using((arena) {
      final pDisplayName = rawName.toNativeUtf16(allocator: arena);
      final pMode = arena<DEVMODE>();
      final mode = pMode.ref..dmSize = sizeOf<DEVMODE>();

      var result =
          EnumDisplaySettings(pDisplayName, ENUM_CURRENT_SETTINGS, pMode);
      if (result == FALSE) {
        print('Failed to get current display settings.');
        return;
      }

      if (mode.dmPelsHeight == height && mode.dmPelsWidth == width) {
        print('Display resolution is already set to ${resolution.prettify()}.');
        return;
      }

      pMode.ref
        ..dmPelsWidth = width
        ..dmPelsHeight = height
        ..dmFields = DM_PELSWIDTH | DM_PELSHEIGHT;

      result = ChangeDisplaySettingsEx(
          pDisplayName, pMode, 0, CDS_RESET | CDS_UPDATEREGISTRY, nullptr);

      if (result != DISP_CHANGE_SUCCESSFUL) {
        print('Failed to change display settings.');
        return;
      }
    });
  }

  /// Returns all supported resolutions of the [Display].
  Iterable<Resolution> get supportedResolutions sync* {
    assert(isConnected);

    final pDisplayName = rawName.toNativeUtf16();
    final pMode = calloc<DEVMODE>();
    final mode = pMode.ref..dmSize = sizeOf<DEVMODE>();

    var modeIndex = 0; // 0 = The first mode
    var previousResolution = (width: -1, height: -1);

    while (EnumDisplaySettings(pDisplayName, modeIndex, pMode) != FALSE) {
      final resolution = (width: mode.dmPelsWidth, height: mode.dmPelsHeight);
      if (previousResolution != resolution) {
        previousResolution = resolution;
        yield resolution;
      }
      modeIndex++;
    }

    free(pMode);
    free(pDisplayName);
  }

  @override
  String toString() =>
      'Display(name: $name, isConnected: $isConnected, isPrimary: $isPrimary)';
}

typedef Resolution = ({int width, int height});

extension on Resolution {
  /// Returns a prettified version of the [Resolution] (e.g. `1920 x 1080`).
  String prettify() => '$width x $height';
}

// TODO(halildurmus): Add these constants into the win32 package

const CDS_FULLSCREEN = 4;
const CDS_GLOBAL = 8;
const CDS_NORESET = 0x10000000;
const CDS_RESET = 0x40000000;
const CDS_SET_PRIMARY = 0x10;
const CDS_TEST = 2;
const CDS_UPDATEREGISTRY = 1;
const CDS_VIDEOPARAMETERS = 0x20;
const CDS_ENABLE_UNSAFE_MODES = 0x100;
const CDS_DISABLE_UNSAFE_MODES = 0x200;
const CDS_RESET_EX = 0x20000000;

const DisplayDeviceStateFlags_AttachedToDesktop = 0x1;

const DISP_CHANGE_SUCCESSFUL = 0;
const DISP_CHANGE_RESTART = 1;
const DISP_CHANGE_FAILED = -1;
const DISP_CHANGE_BADMODE = -2;
const DISP_CHANGE_NOTUPDATED = -3;
const DISP_CHANGE_BADFLAGS = -4;
const DISP_CHANGE_BADPARAM = -5;
const DISP_CHANGE_BADDUALVIEW = -6;

const DM_PELSWIDTH = 0x00080000;
const DM_PELSHEIGHT = 0x00100000;

const ENUM_CURRENT_SETTINGS = -1;

0 replies

dasaintgray · 2023-06-23T00:20:41Z

dasaintgray
Jun 23, 2023
Author

Thank you so much for this, I can't wait to test :)

…

On Thu, Jun 22, 2023 at 5:25 PM Halil Durmus ***@***.***> wrote: Here is an example that enumerates all displays and prints their information. You can set a specific display as primary by calling its setAsPrimary() method. Hope this helps! // ignore_for_file: camel_case_types, constant_identifier_names import 'dart:ffi'; import 'package:ffi/ffi.dart';import 'package:win32/win32.dart'; void main() { // Enumerate all displays and print their information for (final display in Display.findAll()) { print('Display name: ${display.name}'); print('Is connected: ${display.isConnected}'); print('Is primary: ${display.isPrimary}'); if (display.isConnected) { print('Display resolution: ${display.resolution.prettify()}'); print('Supported resolutions:'); for (final resolution in display.supportedResolutions) { print(' - ${resolution.prettify()}'); } } print(''); } // You can use Display.findByName method to find the display you want to set // it as the primary display: // final display = Display.findByName('DISPLAY2'); // if (display != null && display.isConnected) { // display.setAsPrimary(); // } } /// A display monitor.class Display { final String name; final String rawName; final int _deviceIndex; final int _stateFlags; Display._(this.rawName, this._deviceIndex, this._stateFlags) : name = rawName.replaceAll(RegExp(r'[^a-zA-Z\d]'), ''); /// Returns the primary [Display]. static Display get primary => findAll().firstWhere((display) => display.isPrimary); /// Finds a [Display] by its [name] (e.g. `DISPLAY2`). static Display? findByName(String name) => findAll().where((display) => display.name == name).firstOrNull; /// Returns all [Display]s on the system. static Iterable<Display> findAll() sync* { final pDevice = calloc<DISPLAY_DEVICE>(); final device = pDevice.ref..cb = sizeOf<DISPLAY_DEVICE>(); var deviceIndex = 0; while (EnumDisplayDevices(nullptr, deviceIndex, pDevice, 0) != FALSE) { yield Display._(device.DeviceName, deviceIndex, device.StateFlags); deviceIndex++; } free(pDevice); } /// Returns `true` if the [Display] is connected. bool get isConnected => (_stateFlags & DISPLAY_DEVICE_ACTIVE) == DISPLAY_DEVICE_ACTIVE; /// Returns `true` if the [Display] is the primary display. bool get isPrimary => (_stateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE) == DISPLAY_DEVICE_PRIMARY_DEVICE; /// Sets the [Display] as the primary display. void setAsPrimary() { assert(isConnected); if (isPrimary) { print('This display is already set as the primary display.'); return; } using((arena) { final pDevice = arena<DISPLAY_DEVICE>(); final device = pDevice.ref..cb = sizeOf<DISPLAY_DEVICE>(); var result = EnumDisplayDevices(nullptr, _deviceIndex, pDevice, 0); if (result == FALSE) { print('Failed to get display devices.'); return; } final pDeviceName = device.DeviceName.toNativeUtf16(allocator: arena); final pMode = arena<DEVMODE>(); final mode = pMode.ref; result = EnumDisplaySettings(pDeviceName, ENUM_CURRENT_SETTINGS, pMode); if (result == FALSE) { print('Failed to get current display settings.'); return; } final offsetX = mode.dmPosition.x; final offsetY = mode.dmPosition.y; mode.dmPosition.x = 0; mode.dmPosition.y = 0; result = ChangeDisplaySettingsEx(pDeviceName, pMode, 0, CDS_SET_PRIMARY | CDS_UPDATEREGISTRY | CDS_NORESET, nullptr); if (result != DISP_CHANGE_SUCCESSFUL) { print('Failed to change display settings.'); return; } var deviceIndex = 0; // Update remaining displays while (EnumDisplayDevices(nullptr, deviceIndex, pDevice, 0) != FALSE) { final device = pDevice.ref; if (_isAttachedToDesktop(device.StateFlags) && deviceIndex != _deviceIndex) { final pDeviceName = device.DeviceName.toNativeUtf16(allocator: arena); final pMode = arena<DEVMODE>(); final mode = pMode.ref; result = EnumDisplaySettings(pDeviceName, ENUM_CURRENT_SETTINGS, pMode); if (result == FALSE) { print('Failed to get current display settings.'); return; } mode.dmPosition.x -= offsetX; mode.dmPosition.y -= offsetY; result = ChangeDisplaySettingsEx( pDeviceName, pMode, 0, CDS_UPDATEREGISTRY | CDS_NORESET, nullptr); if (result != DISP_CHANGE_SUCCESSFUL) { print('Failed to change display settings.'); return; } } deviceIndex++; } // Apply settings result = ChangeDisplaySettingsEx(nullptr, nullptr, 0, 0, nullptr); if (result != DISP_CHANGE_SUCCESSFUL) { print('Failed to change display settings.'); return; } }); } bool _isAttachedToDesktop(int stateFlags) => (stateFlags & DisplayDeviceStateFlags_AttachedToDesktop) == DisplayDeviceStateFlags_AttachedToDesktop; /// Returns `true` if the [Display] supports the given [resolution]. bool supportsResolution(Resolution resolution) { assert(isConnected); return supportedResolutions.contains(resolution); } /// Gets the [Display]'s current resolution. Resolution get resolution { assert(isConnected); final pDisplayName = rawName.toNativeUtf16(); final pMode = calloc<DEVMODE>(); final mode = pMode.ref..dmSize = sizeOf<DEVMODE>(); try { final result = EnumDisplaySettings(pDisplayName, ENUM_CURRENT_SETTINGS, pMode); if (result == FALSE) { throw Exception('Failed to get current display settings.'); } return (width: mode.dmPelsWidth, height: mode.dmPelsHeight); } finally { free(pMode); free(pDisplayName); } } /// Sets the [Display]'s resolution to the given [resolution]. set resolution(Resolution resolution) { assert(isConnected); if (!supportsResolution(resolution)) { print('Display does not support resolution ${resolution.prettify}.'); return; } final (:width, :height) = resolution; using((arena) { final pDisplayName = rawName.toNativeUtf16(allocator: arena); final pMode = arena<DEVMODE>(); final mode = pMode.ref..dmSize = sizeOf<DEVMODE>(); var result = EnumDisplaySettings(pDisplayName, ENUM_CURRENT_SETTINGS, pMode); if (result == FALSE) { print('Failed to get current display settings.'); return; } if (mode.dmPelsHeight == height && mode.dmPelsWidth == width) { print('Display resolution is already set to ${resolution.prettify()}.'); return; } pMode.ref ..dmPelsWidth = width ..dmPelsHeight = height ..dmFields = DM_PELSWIDTH | DM_PELSHEIGHT; result = ChangeDisplaySettingsEx( pDisplayName, pMode, 0, CDS_RESET | CDS_UPDATEREGISTRY, nullptr); if (result != DISP_CHANGE_SUCCESSFUL) { print('Failed to change display settings.'); return; } }); } /// Returns all supported resolutions of the [Display]. Iterable<Resolution> get supportedResolutions sync* { assert(isConnected); final pDisplayName = rawName.toNativeUtf16(); final pMode = calloc<DEVMODE>(); final mode = pMode.ref..dmSize = sizeOf<DEVMODE>(); var modeIndex = 0; // 0 = The first mode var previousResolution = (width: -1, height: -1); while (EnumDisplaySettings(pDisplayName, modeIndex, pMode) != FALSE) { final resolution = (width: mode.dmPelsWidth, height: mode.dmPelsHeight); if (previousResolution != resolution) { previousResolution = resolution; yield resolution; } modeIndex++; } free(pMode); free(pDisplayName); } @OverRide String toString() => 'Display(name: $name, isConnected: $isConnected, isPrimary: $isPrimary)'; } typedef Resolution = ({int width, int height}); extension on Resolution { /// Returns a prettified version of the [Resolution] (e.g. `1920 x 1080`). String prettify() { final (:width, :height) = this; return '$width x $height'; } } // TODO(halildurmus): Add these constants into the win32 package const CDS_FULLSCREEN = 4;const CDS_GLOBAL = 8;const CDS_NORESET = 0x10000000;const CDS_RESET = 0x40000000;const CDS_SET_PRIMARY = 0x10;const CDS_TEST = 2;const CDS_UPDATEREGISTRY = 1;const CDS_VIDEOPARAMETERS = 0x20;const CDS_ENABLE_UNSAFE_MODES = 0x100;const CDS_DISABLE_UNSAFE_MODES = 0x200;const CDS_RESET_EX = 0x20000000; const DisplayDeviceStateFlags_AttachedToDesktop = 0x1; const DISP_CHANGE_SUCCESSFUL = 0;const DISP_CHANGE_RESTART = 1;const DISP_CHANGE_FAILED = -1;const DISP_CHANGE_BADMODE = -2;const DISP_CHANGE_NOTUPDATED = -3;const DISP_CHANGE_BADFLAGS = -4;const DISP_CHANGE_BADPARAM = -5;const DISP_CHANGE_BADDUALVIEW = -6; const DM_PELSWIDTH = 0x00080000;const DM_PELSHEIGHT = 0x00100000; const ENUM_CURRENT_SETTINGS = -1; — Reply to this email directly, view it on GitHub <#730 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AQH2KEWKOBYRPPEIXHQADODXMQFSBANCNFSM6AAAAAAZPAGHJE> . You are receiving this because you authored the thread.Message ID: ***@***.***>

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Dart | Windows

Set Default Monitor #730

dasaintgray Jun 21, 2023

Replies: 3 comments · 1 reply

halildurmus Jun 21, 2023 Maintainer

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